Quick connect rebar splice

ABSTRACT

A quick connect splice for concrete reinforcement bars includes two diametrically opposed half-shells spanning the aligned ends of the rebars. The half-shells interlock with raised ridges on the bar surfaces to hold the bar ends together. Two sleeve elements slipped over the bars are screwed to each other over the shell sections to secure the splice joint.

This application is a division of Ser. No. 08/982,780 filed Dec. 2,1997, now U.S. Pat. No. 5,967,691.

FIELD OF THE INVENTION

This invention pertains to the field of concrete reinforcement bars usedin poured concrete construction, and more particularly relates to asplice system for joining such bars without turning either bar beingjoined.

STATE OF THE PRIOR ART

Steel reinforcement bars used in poured concrete construction often needto be joined end-to-end so as to make up a longer bar length havingmechanical characteristics approximating those of a single continuousbar of equivalent length. Conventionally, such splices are made by meansof an internally threaded sleeve which makes screwing engagement witheach of the two bar ends to be joined. Such a splice requires that atleast one of the bars be rotated relative to the splice sleeve. Thesleeve can be easily turned and screwed on the first bar end, but inorder to complete the splice joint it is then necessary to either turnthe other bar or both the first bar together with the sleeve screwed onits end. This may require turning by hand long, heavy and cumbersomesteel bars, sometimes under difficult field conditions. This processmultiplied by hundreds or thousands of splice joints in a givenconstruction project adds a considerable labor component to the job andalso lengthens construction time. Also, splice joints are sometimesneeded where it is physically impossible to rotate either bar. This mayoccur where a first bar is already embedded in concrete while the secondbar is bent at an angle with a long bar length extending radially to thesplice axis. In such case, it is usually not possible to turn the bentbar because of physical barriers, such as the ground or other structuralelements.

For these and other reasons, a continuing need exists for a dependableconcrete reinforcement bar splice system which can be installed quicklywithout turning either of the two bars being joined.

SUMMARY OF THE INVENTION

According to this invention a quick connect splice is provided formaking an end-to-end splice joint between two axially aligned concretereinforcement bars of the type having raised surface portions. The novelsplice includes at least two shell sections each having an inner sideconforming to make axially interlocking engagement with the raisedsurface portions, the shell sections being radially assembled to thebars and the shell sections extending axially partially over each of thebars. First and second elements are axially displaceable alongrespective ones of the bars and are engageable to each other for axiallyand radially containing the shell sections in interlocked relationshipwith the bars. The first and second elements may be engaged to eachother by screw threads.

In one form of the invention the first of the elements is a sleevehaving an inner sleeve shoulder axially abutting one end of the shellelements, and the second of the elements is a locking nut threaded tothe sleeve, the locking nut having a nut shoulder axially abutting anopposite end of the shell elements, thereby to secure the sleeve axiallyin radially encompassing relationship over the shell elements.

Preferably, the sleeve has an axial length substantially equal to anaxial length of the shell sections. Each of the shell sections may beapproximately semi-cylindrical and the shell sections are applied to thebars in generally diametrically opposed relationship.

The raised surface portions on the aligned bars may take the form ofannular ridges axially spaced along the bars. In a particular form ofthe invention, the raised surface portions are on an end portion weldedonto the end of each bar at a weld joint of enlarged diameter greaterthan the diameter of the raised surface portions, and the first andsecond elements are axially displaceable over the weld joints betweenthe bars and the welded end portions.

These and other features, advantages and improvements according to thisinvention will be better understood by reference to the followingdetailed description of the preferred embodiments taken in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a presently preferred form ofthe novel bar splice;

FIG. 2 is a longitudinal sectional view of the splice of FIG. 1 prior toassembly;

FIG. 3 is a side view, partly in section, of the splice of FIG. 1 inpartially assembled condition;

FIG. 4 is a side view, partly in section, of the splice of FIG. 1 infully assembled condition;

FIG. 5 is a longitudinal side view, partly in section, of a firstalternate embodiment of the new splice; and

FIG. 6 is a longitudinal side view, partly in section, of a secondalternate embodiment of the new splice;

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the drawings in which like numerals designate likeelements, a splice joint, generally designated by the numeral 10,between two axially aligned generally cylindrical concrete reinforcementsteel bars 12a, 12b, each of which has an end portion 16 terminating atbar end or end face 14. The end portion 16 is threaded with aconventional machine or screw thread 18. In the illustrated embodimentthe end portions 16 are attached to the corresponding bars 12a, 12b by afriction welding process which results in annular extrusions 22 at theweld joint. However, the particular manner of forming or attaching thethreaded end portions to the main body of the bar is not part of thepresent invention and any convenient method of providing the threadedend portions 16 on the two bars may be used. For example, the screwthreads 18 can be produced on forged bar stock in a manner which is wellknown in the art. The main body of each reinforcement bar has surfacedeformations 20 in the form of longitudinal and circumferential ridgeswhich may of conventional design and serve to anchor the bar in a massof poured concrete.

The splice joint assembly 10 includes a pair of approximatelysemi-cylindrical half shells 24, each of which has a semi-cylindricalinterior surface 26 with a thread pattern complementary to the thread 18on the bars 12a, 12b. The half shells 24 are assembled to the two barsso as to bridge the opposite, aligned ends 14 of the two bars to bespliced, as best understood by reference to FIGS. 2 and 3. The two halfshells 24 are applied to the aligned bars 12 in a radial direction andin diametrically opposed relationship, so as to approximate a cylinderradially encompassing and axially bridging the ends 14 of the two bars.Raised portions of the thread pattern 26 of the half shells mates intogrooves of the thread pattern 18 on the bars, as illustrated in FIG. 3,making interlocking engagement in an axial direction between each halfshell 24 and both bars 12a, 12b. An outer sleeve 26, previously slippedaxially onto one bar, bar 12b for example, is then slid onto theassembled half shells 24, to the position shown in FIG. 4,circumferentially encompassing the half shells for securing the halfshells in axially interlocking engagement with the two bars and againstradial separation from the bars.

The splice joint 10 is preloaded in an axial direction by means of twolocking nuts 30, each threaded on a corresponding one of the two bars12a, 12b. The nuts shown are cylindrical in shape, although nuts ofother shapes may be used, and have an outside diameter smaller than theinside diameter of the outer sleeve 26, so that the sleeve 26 may slipaxially over the nuts and away from the bar ends 14, as shown in FIG. 2,in order to permit assembly of the half shells 24 to the axially alignedbar ends. Prior to assembly of the half shells, it is desirable, but notessential that the end faces 14 of the aligned bars be in mutualcontact, as shown in FIGS. 2 and 3.

The nuts 30 are turned and advanced along the threaded portions 16 upagainst opposite sides of the assembled half shells 24 and tightened soas to tension the bars apart from each other against the restraint ofthe assembled half-shells 24. This tensioning has the effect of reducingor largely eliminating free play in the splice joint 10 which otherwisemight occur due to surface roughness and imperfections in the threadsurfaces of both the bar thread 18 and the half shell thread 26. Axialloading of the bars relative to the assembled half shells tends toeliminate gaps and improve contact between opposing thread surfaces inthe splice joint, thereby, distributing the load on the threads over agreater thread surface area. The net effect is that the mechanicalcharacteristics of the resulting splice joint more closely approachthose of a continuous reinforcement bar.

The axial length of the half shells 24 should be, at a minimum, such asto provide sufficient thread contact area to carry the anticipatedmaximum tension load to be carried by the splice joint. The two halfshells 24 can be conveniently made by longitudinally halving aninternally threaded cylindrical sleeve. All components of the splicejoint 10 are made of suitable high strength metal or metal alloys suchas those commonly employed in the manufacture of steel reinforcementsfor cast concrete construction.

Turning now to FIG. 5, a first alternate embodiment of the splice jointis illustrated which differs from the presently preferred embodiment ofFIGS. 1-4 in that the two concrete reinforcement bars 12a', 12b' haveraised annular ridges 34 instead of the helical screw thread 18 of thepreviously described embodiment. The two half shells 24' in FIG. 5 areanalogous to half shells 24 in FIGS. 1-4, except in that the interiorsurface of the half shells 24' has spaced apart radial grooves shapedand dimensioned so as to mate onto the annular ridges 34 of the two barsand thereby make axial interlocking engagement with the bars. That is,when the half shells 24' are applied in diametrically opposedrelationship to the bars, so as to bridge the opposed end faces 14 ofthe two bars, the assembled half shells can be rotated about the barsbut cannot be displaced axially along the bars. The two half shells 24'are held in assembled position about the two bars 12a', 12b' by an outercylindrical sleeve 26' which has an open end 36 and an opposite end 38which is of reduced aperture by an annular lip 42. The open end 36 hasan exterior thread 44 onto which is screwed a locking nut 40 having acomplementary interior thread 46, and a central aperture 48. Prior toassembly the sleeve 26' and locking nut 40 are spaced apart as suggestedin phantom lining in FIG. 5, to permit application of the two halfshells 24' to the ridged end portions of the two bars 12a', 12b'. Thesleeve 26' is then slid axially along bar 12a' to the solid linedposition, and the locking nut 40 is similarly displaced axially alongbar 12b', also to the solid line position. The two pieces 26', 40 arethen screwed to each other, so as to radially encompass an containbetween them the assembled half shells 24', securing the two half shellsagainst separation from the two reinforcement bars and thereby makingthe splice joint.

FIG. 6 illustrates a second alternate embodiment of the splice joint inwhich the screw thread 18 of FIGS. 1-4 is replaced by an upset end 52 ofenlarged diameter which defines an annular shoulder 54 on eachreinforcement bar 50a, 50b. Two half shells 24", each ofsemi-cylindrical shape and having an inner surface with two internalshoulders 56 which complement and mate with the bar shoulders 54, areapplied in diametrically opposed relationship to the two bars bridgingthe end faces 14 of the axially aligned bars 50a, 50b. The interiorshoulders 56 of each half shell make axial interlocking engagement withthe bar shoulders 54 and prevent axial separation of the bar ends. Thetwo half shells 24" are secured in interlocking position with the twobars by means of an outer shell 58 which is advanced from the phantomline position to the solid line position in FIG. 6. The sleeve 58 has aslight conical taper which matches a similar exterior conical taper ofthe assembled half shells 24". The inside dimensions of the taperedsleeve 58 are such as to make a taper lock engagement with the halfshells when the narrow end 62 of the sleeve is tapped, as by means of ahammer, towards the wide end of the assembled half shells, to secure thesplice joint.

It will be appreciated that this invention is not limited to only twosemi-cylindrical shell elements for joining the bar ends. More than twoshell elements may be used, for example three or four cylindricallycurved elements may be applied around the two bars and held together byan outer sleeve. Also, the two or more shell elements may be hingedlyjoined to each other, for example in the form of a clamshell, orotherwise flexibly interconnected so as to allow application of theshell elements to the bars as earlier described.

While a preferred and several alternate embodiments of the presentinvention have been described and illustrated for purposes of clarityand example, it should be understood that still other changes,modifications and substitutions will become apparent to those havingordinary skill in the art without thereby departing from the scope andspirit of the invention defined by the following claims.

What is claimed is:
 1. A quick connect splice for making an end-to-endsplice joint, comprising:two axially aligned generally cylindricalconcrete reinforcement bars having raised surface portions; at least twoshell sections each having an inner side conforming to make axiallyinterlocking engagement with said raised surface portions, said shellsections being radially assembled to said bars, said shell sectionsextending axially partially over each of said bars; and first and secondelements each radially encompassing both said shell sections and axiallydisplaceable along respective ones of said bars and engageable to eachother for axially and radially containing said shell sections ininterlocked relationship with said bars.
 2. The quick connect splice ofclaim 1 wherein said first and second elements have mutually engageablescrew threads for securing said first and second elements to each otherin axially and radially encompassing relationship over said shellelements.
 3. The quick connect splice of claim 1 wherein said first ofsaid elements is a sleeve having an inner sleeve shoulder axiallyabutting one end of said shell elements, and said second of saidelements is a locking nut threaded to said sleeve, said locking nuthaving a nut shoulder axially abutting an opposite end of said shellelements, thereby to secure said sleeve axially in radially encompassingrelationship over said shell elements.
 4. The quick connect splice ofclaim 3 wherein said sleeve has an axial length substantially equal toan axial length of said shell sections.
 5. The quick connect splice ofclaim 1 wherein each of said shell sections is approximatelysemi-cylindrical and the shell sections are applied to said bars ingenerally diametrically opposed relationship.
 6. The quick connectsplice of claim 1 wherein said raised portions comprise annular ridgesaxially spaced along said bars.
 7. The quick connect splice of claim 6wherein said bars each have an end portion welded onto the bar at a weldjoint of enlarged diameter greater than a diameter of said raisedsurface portions, and said first and second elements are axiallydisplaceable over said weld joints between said bars and the welded endportions.
 8. A quick connect splice for making an end-to-end splicejoint, comprising:two axially aligned concrete reinforcement bars, eachbar having an end portion with raised surface portions thereon, said endportion being welded onto the bar at a weld joint of enlarged diametergreater than a diameter of said raised surface portions, at least twoshell sections each having an inner side conforming to make axiallyinterlocking engagement with said raised surface portions, said shellsections being radially assembled to said bars, said shell sectionsextending axially partially over each of said bars; and first and secondelements axially displaceable along respective ones of said bars andover said weld joints, said elements being engageable to each other byscrew threads for axially and radially containing said shell sections ininterlocked relationship with said bars.
 9. The quick connect splice ofclaim 8 wherein said raised portions comprise annular ridges axiallyspaced along said end portions.
 10. A quick connect splice for making anend-to-end splice joint, comprising:two axially aligned concretereinforcement bars having raised surface portions; a pair of generallysemicylindrical shell sections each having an inner side conforming tomake axially interlocking engagement with said raised surface portionson diametrically opposite sides of said bars, said shell sectionsextending axially partially over each of said bars; and a sleeve havingan inner sleeve shoulder axially abutting one end of said shellelements, and a locking nut threaded to said sleeve, said locking nuthaving a nut shoulder axially abutting an opposite end of said shellelements, thereby to secure said sleeve axially in radially encompassingrelationship over said shell elements.
 11. The quick connect splice ofclaim 10 wherein said raised portions comprise annular ridges axiallyspaced along said bars.
 12. The quick connect splice of claim 11 whereinsaid annular ridges are on end portions welded onto said bars, each endportion being welded at a weld joint of enlarged diameter greater than adiameter of said annular ridges, and sleeve and said locking nut eachare axially displaceable across said weld joint.